Sensors for triggering practical Functional Electrical Stimulation walking systems

Functional Electrical Stimulation (FES) techniques have shown significant improvement in mobility and functionality to many patients with pathological gait resulting from upper motor neurological injuries such as stroke, Multiple Sclerosis (MS), etc. Effective functioning of FES walking systems relies on accurate and reliable detection of gait events (i.e heel rise and heel strike) which depends on the type of sensors and the detection algorithm used

Cysteine proteinase C1A paralog profiles correspond with phylogenetic lineages of pathogenic piroplasmids

Piroplasmid parasites comprising of Babesia, Theileria, and Cytauxzoon are transmitted by ticks to farm and pet animals and have a significant impact on livestock industries and animal health in tropical and subtropical regions worldwide. In addition, diverse Babesia spp. infect humans as opportunistic hosts. Molecular phylogeny has demonstrated at least six piroplasmid lineages exemplified by B. microti, B. duncani, C. felis, T. equi, Theileria sensu stricto (T. annulata, T. parva, and T. orientalis) and Babesia sensu stricto (B. bovis, B. bigemina, and B. ovis). C1A cysteine-proteinases (C1A-Cp) are papain-like enzymes implicated in pathogenic and vital steps of the parasite life cycle such as nutrition and host cell egress. An expansion of C1A-Cp of T. annulata and T. parva with respect to B. bovis and B. ovis was previously described. In the present work, C1A-Cp paralogs were identified in available genomes of species pertaining to each piroplasmid lineage. Phylogenetic analysis revealed eight C1A-Cp groups. The profile of C1A-Cp paralogs across these groups corroborates and defines the existence of six piroplasmid lineages. C. felis, T. equi and Theileria s.s. each showed characteristic expansions into extensive families of C1A-Cp paralogs in two of the eight groups. Underlying gene duplications have occurred as independent unique evolutionary events that allow distinguishing these three piroplasmid lineages. We hypothesize that C1A-Cp paralog families may be associated with the advent of the schizont stage. Differences in the invertebrate tick host specificity and/or mode of transmission in piroplasmid lineages might also be associated with the observed C1A-Cp paralog profiles

Diffusion MRI Tractography of the Developing Human Fetal Heart

Objective: Human myocardium has a complex and anisotropic 3D fiber pattern. It remains unknown, however, when in fetal life this anisotropic pattern develops and whether the human heart is structurally fully mature at birth. We aimed here to use diffusion tensor MRI (DTI) tractography to characterize the evolution of fiber architecture in the developing human fetal heart. Methods: Human fetal hearts (n = 5) between 10–19 weeks of gestation were studied. The heart from a 6-day old neonate and an adult human heart served as controls. The degree of myocardial anisotropy was measured by calculating the fractional anisotropy (FA) index. In addition, fiber tracts were created by numerically integrating the primary eigenvector field in the heart into coherent streamlines. Results: At 10–14 weeks the fetal hearts were highly isotropic and few tracts could be resolved. Between 14–19 weeks the anisotropy seen in the adult heart began to develop. Coherent fiber tracts were well resolved by 19 weeks. The 19-week myocardium, however, remained weakly anisotropic with a low FA and no discernable sheet structure. Conclusions: The human fetal heart remains highly isotropic until 14–19 weeks, at which time cardiomyocytes self-align into coherent tracts. This process lags 2–3 months behind the onset of cardiac contraction, which may be a prerequisite for cardiomyocyte maturation and alignment. No evidence of a connective tissue scaffold guiding this process could be identified by DTI. Maturation of the heart’s sheet structure occurs late in gestation and evolves further after birth

Diffusion of triplet excitons in an operational Organic Light Emitting Diode

Measurements of the diffusion length L for triplet excitons in small molecular-weight organic semiconductors are commonly carried out using a technique in which a phosphorescent-doped probe layer is set in the vicinity of a supposed exciton generation zone. However, analyses commonly used to retrieve $L$ ignore microcavity effects that may induce a strong modulation of the emitted light as the position of the exciton probe is shifted. The present paper investigates in detail how this technique may be improved to obtain more accurate results for L. The example of 4,4'-bis(carbazol-9-yl)1,1'-biphenyl (CBP) is taken, for which a triplet diffusion length of L=16 +/- 4 nm (at 3 mA/cm2) is inferred from experiments. The influence of triplet-triplet annihilation, responsible for an apparent decrease of L at high current densities, is theoretically investigated, as well as the 'invasiveness' of the thin probe layer on the exciton distribution. The interplay of microcavity effects and direct recombinations is demonstrated experimentally with the archetypal trilayer structure [N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)]-4,4'-diaminobiphenyl (NPB)/CBP/ 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (named bathocuproine, BCP). It is shown that in this device holes do cross the NPB/CBP junction, without the assistance of electrons and despite the high energetic barrier imposed by the shift between the HOMO levels. The use of the variable-thickness doped layer technique in this case is then discussed. Finally, some guidelines are given for improving the measure of the diffusion length of triplet excitons in operational OLEDs, applicable to virtually any small molecular-weight material.Comment: Accepted for publication in Physical Review

Phase diagram of TTB ferroelectric compounds Pb1−xK2xNb2O6

Substitution of Pb with K in the PbNb2O6 phases leads to a new composition of solid solution with chemical composition Pb1−xK2xNb2O6 with x ranging from 0 to 0.34 in steps of 0.05. Ferroelectric ceramics were synthesized using solid state reaction between the corresponding oxides and carbonates. Powders are pressed and heated into ceramics and their compaction is about 92%. The tetragonal tungsten bronze (TTB) structure at room temperature was confirmed by X-ray diffraction (XRD). The temperature dependence of dielectric permittivity was measured from 35 to 600°C in the 20-106 Hz frequency range. Transition temperature decreases with the lead concentration while from x=0, with Tc=600°C and to x=0.3 with Tc=388°C.  These measurements permit to present a basical phase diagram of this family compound showing the evolution of the characteristic transition temperature Tc versus temperature. The behaviour of Tc is in agreement with theoretical study of the ferroelectric phase transition in TTB using Monte Carlo (MC) simulation. The dielectric properties of these ceramics are similar to those obtained on a single crystal and illustrate the quality of preparative conditions.Substitution of Pb with K in the PbNb2O6 phases leads to a new composition of solid solution with chemical composition Pb1−xK2xNb2O6 with x ranging from 0 to 0.34 in steps of 0.05. Ferroelectric ceramics were synthesized using solid state reaction between the corresponding oxides and carbonates. Powders are pressed and heated into ceramics and their compaction is about 92%. The tetragonal tungsten bronze (TTB) structure at room temperature was confirmed by X-ray diffraction (XRD). The temperature dependence of dielectric permittivity was measured from 35 to 600°C in the 20-106 Hz frequency range. Transition temperature decreases with the lead concentration while from x=0, with Tc=600°C and to x=0.3 with Tc=388°C.  These measurements permit to present a basical phase diagram of this family compound showing the evolution of the characteristic transition temperature Tc versus temperature. The behaviour of Tc is in agreement with theoretical study of the ferroelectric phase transition in TTB using Monte Carlo (MC) simulation. The dielectric properties of these ceramics are similar to those obtained on a single crystal and illustrate the quality of preparative conditions

Transparent code authentication at the processor level

The authors present a lightweight authentication mechanism that verifies the authenticity of code and thereby addresses the virus and malicious code problems at the hardware level eliminating the need for trusted extensions in the operating system. The technique proposed tightly integrates the authentication mechanism into the processor core. The authentication latency is hidden behind the memory access latency, thereby allowing seamless on-the-fly authentication of instructions. In addition, the proposed authentication method supports seamless encryption of code (and static data). Consequently, while providing the software users with assurance for authenticity of programs executing on their hardware, the proposed technique also protects the software manufacturers’ intellectual property through encryption. The performance analysis shows that, under mild assumptions, the presented technique introduces negligible overhead for even moderate cache sizes